Ratchet recliner seat-back mechanism



Jan. 5, w37. c. E. PREBLE RATCHET RECLINER SEAT BACK MECHANISM Filed Jan. 1l, 1934 I u m Z, ma Ww WM www. Nw; lf

I 1 I I T -g1g Patented Jan. 5', 1937 UNITE ATENT OFFICE RATCHE'E RECLINER SEAT-BACK MIECHANSM Application `l'anuary 11, 1934, Serial No. 706,213

3 Claims.

This invention has to do with mechanism for adjusting recliner backs on chairs or seats, especially such as are used in railway cars, buses and the like.

It is an object of the invention to provide a simple and convenient means operable by the occupant of a seat for adjusting the angle of inclination of the back thereof by rotating a handle in one direction or the other, the back being easily and independently movable to its foremost position. Various mechanisms have heretofore been devised for adjusting the angle of inclination of a seat back, one serious objection to such mechanisms being the fact that, in order to put the car or bus into condition for occupancy after a trip, it has been necessary for an attendant to operate the several adjusting mechanisms in order to restore the seat backs to a uniform position so that the car or bus will present an orderly appearance. Mechanism embodying the present invention permits independent movement of the seat back forwardly. Thus, in straightening up a car or bus after a run, it is merely necessary to push on the back of each seat so as to bring it to its foremost position. This saves a great deal of time and effort on the part of the attendant.

The embodiment of the invention hereinafter described and illustrated on the drawing consists primarily of a ratchet-screw device connecting a chair back to an operating handle conveniently mounted in the side arm of the chair.

For a more complete understanding of the invention, reference may be had to the following description and to the drawin-g, of which Figure 1 is a side elevation of a car seat embodying the invention.

Figure 2 is a fragmentary side elevation of the seat-back frame and operating apparatus illustrated in Figure l.

Figure 3 is a fragmentary front elevation of the seat showing the side arm of the operating handle.

Figure 4 is a fragmentary portion of the structure shown in Figure 1, broken away to show the interior parts. l

As shown, the invention may be embodied in a chair I for a railway coach, bus or the like. The chair comprises a pedestal i I, seat frame i2, side arm I3, and back I4. As shown, the back may be hinged as at i5 to the seat frame i2 so as to rock forward and rearward between limiting positions.

A suitable handle 2B may be conveniently mounted for adjustment of the angle of inclination of the back I4, the handle being operatively connected to the back by ratchet-screw mechanism including a thread shaft member and a spring nut member, one of these members being rotatable but not axially movable, the other being axially movable but not rotatable. In the embodiment illustrated in the drawing, the shaft is rotatable. The hand wheel 2] is mounted on a reduced end portion 2| of the shaft 22 which projects through the forward portion of the frame of the chair arm I3. A pair of bearing plates 23 and 24 may be provided, the hub portion of the handle 23 bearing against the plate 23, and a shoulder 25 on the shaft 22 bearing against the plate 24 so as to hold the shaft 22 against axial movement. The reduced portion 2i of the shaft is journaled in the plates 23 and 24 for rotation therein. The rearward portion of the shaft is screw-threaded as at 30, the screw thread being preferably of the ratchet type, that is, with one steep flank and one sloping iiank on the thread. As indicated in Figure 2, the thread is arranged with the steep iiank facing forward and the sloping flank facing rearward so that a spring-pressed pawl can be moved thereover forward but not rearward. Pivotally connected to the frame of the seat back I4, as at 3l, is a link member 32 which may include a tubular portion 33 and a head 35, the portion 33 being adapted to receive the rearward portion of the shaft 22. This head is provided with a transverse bore of suitable cross section in which are slidably mounted a pair of serrated pawls 4l] and 4I which together are equivalent to a nut in threaded engagement with the screw thread 30, each of the pawls being substantially equivalent to a halfnut, as indicated in Figure 2, so that each tooth engages the shaft over nearly a half-turn of the thread, thus providing ample interfacial bearing contact between the shaft and pawls to carry the thrust on the shaft when the mechanism is operated to alter the angle of inclination of the back. The pawls 4i! and 4I may each be provided with a guide pin 42 slidable through a hole 43 in a cover plate 44. A suitable spring 50 may be employed between each pawl and its corresponding cover plate so as to press the pawl yieldingly into engagement with the thread 30.

It is evident that rotation of the shaft 22 by the handle 2t will result in a forward or rearward movement of the pawls 40, 4I, on the thread 3|) of the shaft 22, this motion resulting in a rocking of the seat back i4 forward or rearward according to the direction of rotation of the shaft 22. Since the pawls 40, 4I constituting the nut are yieldable away from the shaft, it is evident. that forward movement of the nut and chair back I4, resulting from rotation of the shaft 22 in the proper direction, will be positive; whereas rearward rocking movement of the chair back, resulting from the rotation of the shaft 22 in the opposite direction, will be yielding, since, if the rearward rocking movement of the chair back is prevented by external obstruction, the pawls 40, 4| will merely ride over the turns of the thread 30 as the latter is rotated. Regardless of the angular position of any chair back equipped with mechanism embodying the invention, it can be instantly restored to its foremost position by a push thereon, the pawls 40, 4I riding on the sloping faces of the thread 30 which force them f away from each other and permit independent forward movement of the chair back i4. Forward rocking of the seat back results in forward movement of the link 32 with respect to the shaft 22 which is not axially movable. When the inner end of the bore in the tubular portion 33 of the link reaches the rear end of the shaft 22, further forward progress of the seat back is stopped. Hence the shaft 22 acts as a stop, cooperating with the link 32 to determine the foremost position of the seat back. In case it is preferred to attach the link member 32 to the seat back at a point below the rocking axis I5, the thread 3D and the teeth of the pawls 40, 4| would be reversed so as to permit independent rearward movement of the link member 32 as the seat back is swinging forward.

It is evident that various modifications and mechanical equivalents can be employed for the purposes of the present invention without departing from the spirit or scope thereof as defined in the following claims.

I claim:-

1. A seat having a rockable back hinged thereto, a link member pivotally connected to said back and extending forwardly, said link terminating in a head, a rotatable shaft having a ratchetscrew threaded portion extending through said head, a pair of opposed transversely slidable pawls carried by said head and yieldingly pressed into engagement with the threaded portion of said shaft, means for preventing axial movement of said shaft, and manually operable means for rotating said shaft.

2. A car seat having a frame, a back rockable on said frame, and mechanism operable in opposite directions to rock said back forward and rearward, said mechanism being effective when actuated in one direction to rock said back positively forward and when actuated in the other direction to rock said back yieldingly rearward, said mechanism including telescoping relatively rotatable members, one of which is pivoted to said back and the other of which is pivoted to said frame.

3. A car seat having a frame, a back rockable on said frame, and mechanism operable in opposite directions to rock said back forward and rearward, said mechanism being effective when actuated in one direction to rock said back positively forward and when actuated in the other direction to rock said back yieldingly rearward,

said mechanism including a rotatable shaft pivoted near its forward end to said frame, and a non-rotatable member telescoping a portion of said shaft and in threaded engagement therewith, said member being pivotally attached to said back.

CLARENCE E. PREBLE. 

